Controlled release interproximal delivery system

ABSTRACT

The present invention discloses dental floss containing surfactant and silicone preparations with added chemotherapeutic agents.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a continuation of application Ser. No. 07/453,302 filed on Dec.20, 1989, abandoned and a continuation in part of Ser. No.07/270,132--Filed Nov. 14, 1988, now abandoned and a continuation inpart of Ser. No. 07/270,135--filed Nov. 14, 1988, now abandoned and acontinuation in part of Ser. No. 07/270,163--filed Nov. 14, 1988, nowabandoned and a continuation in part of Ser. No. 07/270,167--Filed Nov.14, 1988, now abandoned and a continuation in part of Ser. No.07/270,544--Filed Nov. 14, 1988, now abandoned and a continuation inpart of Ser. No. 07/270,723--filed Nov. 14, 1988, now abandoned and acontinuation in part of Ser. No. 07/270,562--Filed Nov. 14, 1988 nowU.S. Pat. No. 4,911,927; the disclosures of which are herebyincorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to oral hygiene and specifically to aninnovative interproximal delivery system comprising a dental floss withimproved cleaning, conditioning and antimicrobial properties, the flossfurther containing chemotherapeutic agents, e.g., antimicrobials,antibiotics, antioxidants, desensitizers, and anti-tartar agents, suchas tetracycline, chlorhexidine, sodium fluoride, stannous fluoride, andpolyvinyl pyrollidone iodine complex with iodine.

BACKGROUND OF THE INVENTION

Proper use of dental floss is necessary to clean the considerable areaon the interproximal surfaces of teeth, which cannot be reached by thebristles of a toothbrush.

The purpose of dental floss is:

1. to dislodge and remove any decomposing food material that hasaccumulated at the interproximal surfaces that cannot be removed bybrushing, and

2. to dislodge and remove as much as possible the growth of bacterialmaterial (plaque) upon the teeth or the superimposed calculus that hasaccumulated there since the previous cleaning. Plaque is discussedbelow.

The concept of the use of dental floss for cleansing interproximalspaces appears to have been introduced by Parmly in 1819 ["PracticalGuide to the Management of the Teeth," Collins & Croft, PhiladelphiaPa.]. Parmly suggested the use of waxed silk to clean teeth of personssubject to gingival inflammation. Numerous types of floss were developedand used for cleaning, until finally in 1948 Bass established theoptimum characteristics of dental floss. (Dental Items of Interest, 70,921-34, (1948)).

Surprisingly, floss marketers have ignored Bass for the past 40 years.Bass warned that dental floss treated with sizing, binders and/or waxproduces a "cord" effect which reduces flossing efficiency dramatically.Almost all floss sold today including unwaxed floss contains bindersand/or sizing substances. These "sticky" substances are used to keep thefloss twists from unwinding during use and to keep the floss turns fromfalling off a spool during dispensing by holding the floss together.

Additionally, most floss sold at retail today is also "waxed" to assistpenetration to interproximal regions; as the "cord" effect described byBass makes the floss bundle difficult to force between closely spacedteeth.

The optimum characteristics of dental floss as described by Bass in 1948are ignored by today's flosses. Specifically, Bass suggests that thesewaxed and sized flosses produce the "cord" effect discussed above asdistinguished from the "spread effect" of unwaxed, unsized floss whichflattens out and widens, with the filaments spread out. The potentialfor separate mechanical action of spread out filaments is nullified bythis "cord" effect, as are the spaces between the filaments, whichaccording to Bass are necessary to receive, hold and remove themicroscopic material dislodged during flossing. Thus, the mechanicalcleaning attributed to spread filaments and essentially all of theevacuation of microscopic materials from the interproximal spaces byentrapment is impaired or sacrificed with waxed and/or sized flosses,because of this "cord" effect.

As an alternative to sizing, binders, wax etc., Bass suggests "steamset"to set the twist in dental floss so that the floss will not untwistduring use. Commercial floss twisters and floss spoolers, opted to usevarious binders and sizing materials instead. These "sticky" substancesfacilitate floss handling, keep the floss from untwisting during use,and keep the floss from falling off the spool. Although steamset flossdoes not untwist during use, absent sticky substances, it does unraveloff the spool during dispensing and during spooling. Thus, the optimumfloss described by Bass could not be manufactured commercially in 1948,so apparently, water insoluble binders, sizing and wax were adoptedearly on and continue up to the present.

From 1960 thru 1962, numerous clinical studies reported that there is noclinical difference as to plaque removal and gingivitis scores betweenwaxed and unwaxed dental floss. Note, both are "cord" flosses andcontain sizing, binders etc. These studies also confirmed that waxed andunwaxed floss are approximately 50% effective with respect to plaqueremoval and gingivitis scores. Thus the "cord" effect severely restrictsefficiency of flossing.

O'Leary in 1970, and Hill et al. in 1973, found no difference in theinterproximal cleansing properties of waxed or unwaxed dental floss.This was reconfirmed in 1982 by Lobene et al. [Clinical PreventativeDentistry, Jan-Feb] who showed no significant clinical difference onplaque and gingivitis scores. Similar results, i.e., no clinicaldifference between waxed and unwaxed floss with respect to reducedgingival inflammation were shown by Finkelstein in 1979 [J. Dent. Res.,58: 1034-1039]. No differences in gingival health were shown byWunderlich in 1981 [J. Dent. Res., 60A: 862]. No differences in plaqueremoval were reported by Schmidt et al. in 1962 [J. Dent. Res.] withflosses of various types. Stevens in 1980, studied floss with variablediameters and showed no difference in plaque and gingival health. Carteret al., Va Dent. J., 52: 18-27 (1975), studied professional andself-administered waxed and unwaxed floss, both significantly reducedgingival bleeding of interproximal and gingival sulci. Unwaxed flossappeared slightly, but not significantly more effective.

In view of this clinical work, it is not surprising that most of thedental floss sold today is bonded and/or waxed. The "bonding" in theyarn industry today is used more to facilitate processing and productionduring floss manufacture and packaging than for "flossing" reasons.Since clinical tests show no difference between waxed and unwaxed floss(both unfortunately are "bonded") the floss industry has beencomfortable with the yarn industry's propensity to use bonding agents infloss.

Today there are three basic nylon strand constructions approved by theFDA for flossing. These are 140 denier (68 filament), 100 denier (34filament), and 70 denier (34 filament). Analysis of the commercialflosses sold worldwide show that almost all flosses available aretwisted in generally the same manner, contain bonding agents, and areconstructed by twisting several (6-10) strands selected from one ofthese three strand types.

Almost 100% of the floss sold today is manufactured by "yarn"manufacturers with little consideration given to the influence oftwisting of floss construction on cleaning, etc.

The simple removal of binders, to allow the floss strands to spread out,introduces a "user-unfriendly" effect which reduces the value Bassdescribed. Commercial flosses with little or no binders are notoriousfor frustrating flossers with their tendency to fray, break etc. Theremoval of binders requires adjunct (lubricants, etc.) to reducesnagging, fraying, etc.

In view of the foregoing, it is not surprising that shred resistantfloss has been the basic claim of some floss marketers. The most recentintroduction of a Goretex™ type floss, with its monofilamentconstruction, should prove to be the ultimate shred resistant floss.Historically, the typical response to shredding was to develop a"tighter" bonded and smaller diameter floss that did not spread out anddid not shred. Waxing was also an option. It is not difficult to see howthe "ultimate cord", i.e., monofilament construction, evolved from thisapproach. The monofilament floss is reported to be easier to use thantraditional bonded flosses.

Somehow it has become generally accepted throughout the oral carecommunity today that:

1. the daily mechanical disruption and removal of dental plaque with astandard bonded dental floss is a very effective method of interproximalplaque control, and

2. it would be difficult to demonstrate clinical superiority over thestandard commercial flosses.

This conclusion contradicts the mediocre plaque and gingivitis controleffect of standard floss as reported consistently in the literature, towit:

1. The literature has repeatedly documented that gingivitis scoresflattened after 4 weeks of flossing with scores routinely in the 60's.See Lobene et al. and other waxed v. unwaxed dental floss studies.

2. Many researchers report that the best floss in the hands of expertswill only remove 50 to 60% of the interproximal plaque.

3. Keene in 1976 [J. Am. Dent. Assoc., 93: August], reported that ". . .ordinary waxed dental floss was neither an efficient debriding agent noran effective tool for delivery of the test agents to the interproximalsites", and

4. Additionally, Finkelstein and Grossman, supra, Hill et al., supra,Carter et al., [J. Periodont., 44: 411-413 (1973)], Wunderlich et al.,supra, Schmid et al., J. Dent. Res., 60A: 122 (1981), Lamberts et al.,and Stevens, each showed plaque reductions and/or improved gingitivityor improved gingival health with flossing. These results were comparableto Lobene et al., i.e., that floss was 50% to 60% effective, and thustraditional floss leaves room for substantial improvement.

There is, therefore a definite need in the art for an improved dentalfloss, to clean, condition and treat the surfaces flossed.

SUMMARY OF THE INVENTION

Proper flossing procedure as recently described in "Dental HealthAdviser" includes: "slide it (floss) between your teeth using a gentlesawing action" and "scrape the sides of your teeth with an up and downmotion".

The present invention is based upon the discovery that this type ofmechanical action can be supplemented by the release of surfactants fromthe floss into the interproximal region. These released surfactants arereadily solubilized in saliva and interproximal fluids to produce adetersive effect in the interproximal region during flossing. Foaming ofthe surfactant is avoided by the use of silicone conditioners, thusoptimizing this detersive effect.

Thus, the present invention may be broadly defined as an interproximaldelivery system comprising a unique dental floss, said floss containinga cleaning preparation comprising a surfactant and a coating substanceat from between 5 and about 100% by weight of the weight of the flossstrands, and optionally further containing up to about 50% by weight ofan active chemotherapeutic agent selected from the group consisting ofantimicrobials, antibiotics, antioxidants, desensitizers, andanti-tartar agents.

The surface active properties of the surfactant and silicone presentedinterproximally, not only assist in cleaning debris and plaque from theinterproximal sites, and condition teeth and gums but they also alterthe surface tension of the plaque remaining; as well as disruptingplaque matrix reattachment.

The method of treating the oral cavity with these flosses is describedin the following copending applications:

(1) Ser. No. 07/270,161 --Filed Nov. 14, 1988, entitled Method ofTreating the Oral Cavity with Dental Floss Containing Tetracycline, nowabandoned;

(2) Ser. No. 07/270,162 --Filed Nov. 14, 1988, entitled Method ofTreating the Oral Cavity with Dental Floss, now abandoned;

(3) Ser. No. 07/270,164 --Filed Nov. 14, 1988, entitled Method ofTreating the Oral Cavity with Dental Floss Containing PolyvinylPyrollidone Iodine Complex, now abandoned;

(4) Ser. No. 07/270,166 --Filed Nov. 14, 1988, entitled Method ofTreating the Oral Cavity with Dental Floss with Chlorhexidine, nowabandoned; and

(5) Ser. No. 07/270,353 --Filed Nov. 14, 1988, entitled Method ofTreating the Oral Cavity with Dental Floss with Stannous Fluoride, nowabandoned.

the disclosures of which are hereby incorporated herein by reference.

This improved lifting of debris, plaque and soil from the interproximalspaces with surfactants is further enhanced by the use of unbonded flossstrands which spread out and follow the contours of the teeth duringflossing/cleaning. This improved mechanical cleaning is furthersupplemented with various insoluble abrasives released interproximallyfrom the floss during flossing. This combination of abrasive, surfactantand mechanical action is more efficient than mechanical action alonewith waxed floss.

The floss of the present invention may be more appropriately describedas a local delivery system, suitable for the topical cleaning and/ortreatment of those hard-to-reach areas between teeth (interproximalspaces) and the areas immediately below the gumline (i.e., the gingivalcrevice).

The unique construction of the floss and loading of cleaners, activeingredients and conditioners in the space around each of the nylonfibers allows loading of these substances from 10 to over 100% by weightof the floss. The "loaded" floss tends to "splay" (open up), whenpressure is applied to the floss, i.e., the pressure required to fit thefloss between teeth and/or, after the floss is positioned between teeth,the pressure applied during flossing. When the floss is splayed, theloaded substances are released and continue to be released during thesawing motion of flossing. This releasing action supplements thecleaning action of flossing by releasing cleaners to work with thefloss.

In a preferred embodiment, the present invention may be defined as aninterproximal delivery system comprising:

a. floss having from between two and 12 strands, each containing betweenabout 100 and 800 filaments with a denier between 300 and about 1200,and

b. a cleaning preparation at from between 5 and about 100% by weight ofsaid strands, wherein:

i. said filaments are substantially free from sizing and binding agents;

ii. said interproximal delivery system splays upon being worked betweeninterproximal surfaces;

iii. said interproximal delivery system release from between about 10and about 80% by weight of said cleaning preparation upon splaying; and

iv. said cleaning preparation:

a. is loaded into said delivery system as a substantially aqueous free,hot-melt emulsion,

b. is contained throughout the interproximal delivery system, primarilyin the area surrounding said filaments with less than about 5% by weightof said cleaning preparation on the outermost surface of said deliverysystem, and

c. can contain up to about 50% by weight of an active chemotherapeuticagent selected from the group consisting of: antimicrobials,antibiotics, antioxidants, desensitizers, and anti-tartar agents.

The following features of the present invention characterize thesurfactant/silicone/abrasive enhancement effect produced when flossinginterproximally: 1. Rapid release of substantial quantities of salivasoluble surfactant, silicone and abrasive when the floss is pulledacross tooth surfaces. The construction of the floss, the use ofunbonded floss, the absence of wax and a unique loading process whichencourages the floss to open up and release the load during flossing.

2. Rapid solubilization of a surfactant with high detergency, and salivasolubility, combined with simethicone produce excellent detersiveresults with no foaming, and

3. The tendency to use "fresh" loaded floss is for each interproximalsite flossed. The addition of hedonic substances, flavor oils, silicone,"mouth-feel" affecting gums, etc. to the load encourage the flosser tounwind fresh floss prior to flossing a new site. Thus, the flosser ishedonically driven to use fresh floss with the present invention.

The potential development of hedonically superior flosses has beensurprisingly restricted and may be a critical factor in the failure offlossing and may be a critical factor in the failure of flossing topenetrate more than about 10% of the adult U.S. market.

The superior flavored flosses available commercially are based on"encapsulated flavor" technology where the flavors are delivered in aspray dried matrix form to the bonded floss. See U.S. Pat. No.3,943,949, the disclosure of which is hereby incorporated herein byreference. These flavored flosses are available waxed or unwaxed. Lesseffective application application and retention of flavor is alsocommercially achieved by direct contact of the floss with flavoroil/solvent solutions. The inherent limitations of the encapsulatedflavored flosses are evident when these products are compared to "flavoroil in a solidified melt emulsion" treated flosses of the presentinvention.

Other hedonic areas critical to a positive consumer response towardsflossing such as "mouth feel" have not been addressed by current flossproducts.

It is generally accepted that floss is not a "user-friendly" product,i.e., it is difficult to do. It causes pain and bleeding and it resultsin a bad taste in the mouth. Most market researchers agree that anythingthat can be done to make flossing more positive should be implemented toencourage more frequent flossing and more wide spread floss use. Theaddition to floss of: full spectrum flavor oils, mouth conditioningsubstances such as silicones, and cleaners and abrasives that leave a"clean, just brushed feeling" as taught by the present invention are allsources of positive feed back to the flosser that would be consideredencouraging and supportive. To achieve these requires basic changes infloss construction, physical chemistry of floss additives and new"loading" technology that goes beyond waxing and the "yarn" (cord)approach to floss construction.

With the advent of "loading active ingredients" into floss for releaseduring flossing as discussed below, the opportunity is available toinclude desensitizing agents into the load to minimize flossing pain anddiscomfort. Typically, desensitizing agents such as strontium chlorideare used in dentifrices for "sensitive" teeth. These substances producea comparable effect when released interproximally from the floss of thepresent invention. This desensitizing effect further improves theoverall hedonics of the floss of the present invention. Examples offloss of the present invention with desensitizers as an addedchemotherapeutic agent are described below.

Analysis of current waxed floss users shows a consistent tendency to"re-use the floss" and not to use a fresh piece of floss for eachinterproximal site. The spent "waxed" floss, under close inspectionshows little entrapped, dislodged microscopic particle because of the"cord" effect.

In contrast, as noted above users of the floss of the present inventionshow a consistent tendency to use "fresh" floss for each newinterproximal region. Additionally, the "spent" floss of the presentinvention contains entrapped substances which can be observed by theflosser. This tends to motivate the use of fresh floss as well. Themouth feel and taste imparted by the floss reinforces that the floss isworking by leaving a clean, fresh feeling in the mouth.

Surprisingly, when the chemotherapeutic agents of the present inventionare added to floss strands they perform one critical function of thestandard size or binder in that they keep the floss from untwistingduring use and impart the "stickiness" necessary to allow the floss tobe spooled and dispensed without unraveling. However, because of thechemistry of these substances and the loading process used; contrary tothe bonded or waxed floss, the loaded floss of the present inventionspreads out during use to obtain the separate mechanical action of themany filaments.

This spreading out during flossing, also triggers the release mechanismwhich discharges most of the load interproximally during flossing, i.e.,up to about 80% by weight. The surfactant/silicone/abrasive mixturethus, released is readily solubilized in the saliva and other fluidspresent. This solubilized mixture responds to the separate mechanicalaction of the floss filaments resulting in a nonfoaming detersive effectin the interproximal space.

Release of the load leaves spaces in the floss which tend to take up andhold some of the microscopic substances dislodged during flossing. These"captured" substances can be easily observed in the "spent" floss.

The floss of the present invention is preferably a nylon dental flossthat has been processed to load into it up to about 80 mg/yd of thecleaning and plaque fighting formulation described in copendingapplication Ser. No. 06/927,752, filed Nov. 6, 1986, entitled "Dentaland Oral Hygiene Preparations," the disclosure of which is herebyincorporated herein by reference.

Up to about 80% of this load is released onto interproximal andsubgingival sites during flossing, i.e., up to about 64 mg/yd. Thisrelease of surfactant cleansing in the area flossed is not availablewith flosses sold today. The flosses of the present invention showsuperior cleaning over waxed or unwaxed commercial flosses.

Additionally, the floss of the present invention can contain therapeuticsubstances for release at concentrations up to 40 mg/yd. When thesesubstances are included in the load they are released onto thoseinterproximal and subgingival sites which cannot be reached by rinsingor brushing. This interproximal release of substances in theseconcentrations is unique, in that it improves plaque control andgingivitis scores over other dental flosses.

Most authorities agree that the control of periodontal diseasesrequires:

1. regular disruption of subgingival microflora, and

2. regular removal of supergingival plaque.

Many rinses and dentifrices claim supragingival control of plaque and/ortartar. None are proved effective subgingivally and have limitedsupragingival effect interproximally. Floss has been proven to have somesubgingival mechanical disruption value, but no chemotherapeutic valuesubgingivally or supergingivally.

In contrast, regular flossing with the floss of the present inventionprovides a unique combination of mechanical action, detersive action,surface modification and chemotherapy which results in:

a. disruption of subgingival microflora, and

b. removal of interproximal supragingival plaque.

Subgingival chemotherapeutic disruption of microflora is achieved by theunique combination of:

a. chemical cleansing with surfactants released form the floss of thepresent invention,

b. prolonged modification of the surface chemistry of the microflora bythe coating materials released, e.g., silicones, released from thefloss, and

c. alteration of microflora with various active ingredients contained inthe load and released during flossing.

Subgingival mechanical disruption of microflora is achieved by theunique combination of:

a. physical disruption by the "spread-out", lubricated floss fibers,

b. abrasive, disruption with abrasives released from floss including:silica, dicalcium phosphate, pyrophosphates etc., at concentrations upto 40 mg/yd; and

c. surfactant disruption resulting from the release of surfactantsduring flossing.

Chemotherapeutic removal of supergingival plaque is achieved by theunique combination of:

a. chemical cleansing with surfactants released from the floss,

b. modification of the surface chemistry of the plaque with coatingmaterials e.g., silicones, and

c. alteration of the plaque with various active ingredients contained inthe load and released during flossing including: tetrasodiumpyrophosphate, tetrapotassium pyrophosphate etc.

Mechanical removal of supragingival plaque is achieved by the uniquecombination of:

a. physical removal by the unbonded, spread out, lubricated flossfibers,

b. abrasive removal by the abrasives released from the floss including:silica, dicalcium phosphate, pyrophosphates etc., and

c. cleansing resulting from the release of surfactants during flossing.

Plaque is a microbially formed coating on tooth surfaces, bound togetherby natural polymers, (mucopolysaccharides) formed by a microbial actionon salivary fluids, cell debris, food remnants, sugars and starches inthe mouth. Embedded in this polymer matrix are the bacteria normal tothe oral cavity but, when rapped against tooth surfaces and protected bythe matrix from easy removal, are in excellent position for "mischief".Most dental texts implicate plaque in the formulation of caries, ortooth decay. In addition, these embedded bacteria release toxins thatcause gingivitis, bleeding and swelling of the gums. Gingivitis can leadto periodontitis in which gums recede, pockets of infection form andteeth loosen.

Plaque formation is an ongoing process. Various gel and paste dentifricepreparations, mouth rinse and mouth prerinse preparations, make plaqueand/or tartar control claims. One disadvantage of these preparations isthat only a relatively short time during which the teeth are beingcleaned or the mouth is being rinsed is available for these preparationsto take effect. These preparations generally have little residual effecton plaque formation. Further these rinses are limited to supragingivalplaque and tartar control and have little access to the criticalinterproximal area. In contrast, the floss of the present inventionreleases substances interproximally and subgingivally. Additionally,some of these preparations such as mouth rinses and prerinses containvarious antimicrobial substances which may alter the critically balancedmicroflora of the mouth. Generally, these substances are introduced intothe oral cavity in large quantities due to the dilute nature of thedelivery vehicle.

Effective oral hygiene requires that three control elements bemaintained by the individual:

1. Physical removal of stains, plaque and tartar. This is accomplishedin the strongest sense by scraping and abrasion in the dentist's office.Self administered procedures are required frequently between visits andrange from tooth brushing with an appropriate abrasive toothpastethrough flossing and water jet action down to certain abrasive foods andeven the action of the tongue against tooth surfaces.

2. Surfactant Cleansing. This is required to remove: food debris andstaining substances before they adhere to the tooth surfaces; normaldead cellular (epithelial) material which is continually sloughed offfrom the surfaces of the oral cavity and microbial degradation productsderived from all of the above. Besides the obvious hygienic and healthbenefits related to simple cleanliness provided by surfactants, there isan important cosmetic and sense-of-well-being benefit provided bysurfactant cleansing. Research has shown that the primary source of badbreath is the retention and subsequent degradation of dead cellularmaterial sloughed off continuously by the normal, health mouth.

3. Frequency of Cleansing. This is perhaps the most difficult to providein today's fast-paced work and social environment. Most people recognizethat their teeth should be brushed at least 3 times a day and flossed atleast once a day. The simple fact is that most of the population brushonce a day, some brush morning and evening, but precious few carrytoothbrush and dentifrice to use the other three or four times a day foroptimal oral hygiene. Consumer research suggests that the populationbrushes an average of 1.3 times a day. Most surprising, less than 10% ofadults floss regularly. Reasons offered for not flossing; difficult todo, painful, not effective and leaves a bad taste. Overall, floss is nota "consumer friendly" product.

Since plaque is regarded by most of the dental profession as a causativeagent leading to various dental pathologies discussed in detail below,there is considerable desire by most consumers to remove or prevent theformation of plaque on a daily basis.

There are four oral care techniques which address the problem of plaque:abrasion, antimicrobial agents, removal of precursors to plaque, andaltering the attachment of plaque to a surface.

1. Abrasive removal of the plaque film, once it has firmly adhered tothe tooth surface, is the only totally effective cleansing mechanism.Again, professional dental hygiene is most effective, but recently, anumber of special abrasive toothpastes have been accepted by dentalorganizations for partially removing supragingival adhered plaque andthe tartar which subsequently forms from the plaque. Heretofore,interproximal plaque could only be removed by mechanical means such asflossing and/or by use of appropriately shaped dental stimulators.Dental stimulators containing the substances of the present inventionare disclosed in copending application Ser. No. 07/270,165 filed Nov.14, 1988, entitled "Dental Stimulator," the U.S. Pat. No. 4,942,034disclosure of which is hereby incorporated herein by reference.

2. Antimicrobial action can affect plaque formation in two ways, (a)reducing the number of bacteria in the mouth which form themucopolysaccharides and (b) killing those bacteria trapped in the filmto prevent further growth and metabolism. However, the medical anddental community is divided about the advisability of frequent use ofantimicrobial agents in the mouth in rinses or prerinses, especially themost effective ones, except under strict supervision of licensedpractitioners. There are a number of reasons given, but one concern isthat such materials would upset the ecological balance of the mouth. Abalanced, "friendly" microbial population is necessary to preventpathogenic organisms from taking over.

By contrast, delivery of antimicrobial agents directly to the criticalsites would more effectively treat the disease or pre-disease conditionwith localized concentrations. The microflora of these sites could bealtered with appropriate substantive antimicrobials. Obviously, a moreeffective cleansing and physical removal, such as provided by thepresent invention, reduces even further the required totalconcentrations of antimicrobials required to produce efficacy.

3. Removal of plaque precursors requires the reduction of food sourcesand building blocks required for the bacteria to synthesize themucopolysaccharides which polymerize into the plaque film. Going farback into the chain of evens leading to plaque formation andinterrupting the chain has much to commend it as a sound oral hygienestrategy. However, for this technique to be effective, the plaquebuilding blocks must be interrupted periodically throughout the mouth,especially at the site of plaque buildup and if possible just below thetooth-gum interface and interproximally. Such disruption is described incopending applications Ser. Nos. 927,752 now U.S. Pat. No. 5,032,387 and927,805 now U.S. Pat. No. 4,950,479 filed Nov. 7, 1986, the disclosuresof which are hereby incorporated herein by reference. Most other oralhygiene preparations described above fall short on "frequency-of-use"basis, abrasion and cleaning. For reference see, L. Menaker, "TheBiologic Basis of Dental Caries", Chapters, 5, 11, 12, 14, 16 and 18,Harper and Row (1980).

4. As to altering attachment of plaque, it has now been found that thecleaning and coating compositions described below can be incorporatedinto dental floss of specified construction at surprisingly highconcentrations; considering that the compositions of the presentinvention are not soluble in the floss. Secondly, floss so treated will"release" these compositions during flossing and chemically cleanse thearea of plaque and plaque precursors, bacteria, etc., while coatingteeth and gum surfaces with a plaque matrix disrupting substance. Therelease of these substances is particularly effective in disrupting, forprolonged periods, the plaque matrix on these interproximal sites. Thecleaning that results from the compositions released from the floss alsotakes place on those interproximal surfaces brushing does not reach.This chemical cleansing and matrix disruption adds a new dimension toflossing beyond the physical removal of debris from these surfaces.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The floss of the present invention comprises:

a multi strand dental floss containing, an ingestible, nonfoaming,plaque disrupting composition comprising cleaners and coating substancesdispersible in said cleaners wherein:

a. the multi-strand floss:

1. contains from between 2 and 12 strands,

2. has a denier between about 300 and about 12,000, and

3. contains between about 100 and about 800 filaments;

b. the strands include natural and/or synthetic fibers and mixturesthereof including cotton, silk, polyester and nylon;

In a preferred embodiment of the present invention the floss is nylon,contains between 4 and 8 strands, with a denier between about 500 and1000 and contains between about 200 and 600 filaments. In a particularlypreferred embodiment of the present invention the floss is nylon,containing 6 strands, has a denier of about and has approximately 408filaments.

c. the cleaners include: surfactants and emulsifiers such as:

sodium lauryl sulfate,

sodium lauroyl sarcosinate,

polyethyleneglycol stearate,

polyethyleneglycol monostearate,

coconut monoglyceride sulfonates,

soap powder,

sodium alkyl sulfoacetates,

alkyl polyglycol ether carboxylates such as those described in U.S. Pat.No. 4,130,636;¹

polyoxyethylene derivatives of sorbitan esters, such as those describedin U.S. Pat. Nos. 3,639,563,¹ 3,947,570,¹

propoxylated cetyl alcohol as described in U.S. Pat. No. 2,677,700;¹ and

preferred commercially available substances which include:

polyoxyethylene, polyoxybutylene block copolymers such as Pluronic F108,and F127 (BASF) and polysorbates such as Tween 40, and 80, (Hercules).

Particularly preferred surfactants include block copolymers comprising acogeneric mixture of conjugated polyoxybutylene and polyoxyethylenecompounds having as a hydrophobe, a polyoxybutylene polymer of at least1200 molecular weight; such as described in U.S. Pat. Nos. 4,343,785,4,465,663, 4,511,563 and 4,476,107,² and

d. the coating substances can be characterized as follows, they:

1. suppress the tendency of the surfactant cleaners that are present tofoam,

2. are safely ingestible at the concentrations used,

3. have an affinity for mouth and teeth surfaces,

4. are neutral, inert and do not support biological activity,

5. modify the surface energy properties of oral cavity surfaces suchthat it is more difficult for food particles, cellular debris andvarious plaque precursors and formers to attach to these oral cavitysurfaces,

6. form a fugitive thin, transparent coating that does not build up onoral cavity surfaces and is removed by the normal clearing and flushingaction of the mouth,

7. impart a pleasant "smooth" feeling to the surfaces of the mouth, gumsand teeth, and

8. retain various flavors, sweeteners and pharmacologically preparationsactive on surfaces of the mouth imparting an unexpected prolonged effectof the pharmacologically active substances as well as prolonged flavorperception, and

9. The preferred coating substances include:

various silicones,

carbowaxes,

polymers such as: silicone glycol copolymers,

polydimethyl siloxanes,

long chain hydrocarbons, especially normal paraffins having a chainlength of 16 carbon atoms or greater, paraffins with several loci ofbranching and unsaturation, where the extent of such branching andunsaturation does not create unacceptable toxicity nor lower thesolidification point below body temperature, and

polymers which have limited solubility in ethanol and water solutionswhere the ethanol; water ratio is greater than 0.3:1 but haveessentially no solubility in water or saliva at lower ratios.

The combination of these cleaners with these coating substances, whereinthe latter is inherently insoluble in the former, in a treated dentalfloss is novel. The prolonged plaque matrix disruption so obtained witha floss containing this combination in the mouth, is novel.

Furthermore, the cleaner, coating substance, and saliva or gingivalcrevice fluid mixture obtained when the compositions are released in themouth are ingestible and can be pleasantly swallowed, which furtherdistinguishes it from typical oral cleaning compositions used with atoothbrush and most rinses and prerinses. For example, unlike typicalcleaners used in dentifrice pastes, the cleaners of the presentinvention do not fill the mouth with foam and can be pleasantlyswallowed which is necessary for those flosses loaded with substantialquantities of releasable materials.

The compositions released from the floss during flossing can disruptplaque formation without resort to antimicrobial ingredients. Thevarious surfaces of teeth and gums are coated with a smooth thin filmreleased from the floss which disrupts plaque formation. These coatingsremain in the interdontal spaces for extended periods and prolong thisdisruption effect on plaque matrix formation.

Alternatively, for those useful embodiments of the present inventionwhere specific localized antimicrobial ingredients are therapeuticallydesirable, these compositions provide an excellent carrier. Thus, thefloss may additionally comprise one or more chemotherapeutic agents, forexample, tetracycline, chlorhexidine, sodium fluoride, stannousfluoride, and/or polyvinyl pyrrolidine iodine complex, to mention but afew. Given the teachings of this disclosure, the skilled artisan willreadily be able to supplement this list of chemotherapeutic agents withthose desired for any particular application.

A review of the construction of the floss of the present invention showsthat the compositions of the present invention are contained essentiallyin the interstitial spaces between the fibers of the floss with minimumcomposition on the outer surface of the floss. This internal loading ofthe compositions is achieved by opening up the floss fibers duringmanufacturing and introducing a melt-emulsion of the compositions of thepresent invention into the space around the opened fibers.

The floss of the present invention is unique in its capacity to releasethe "loaded" compositions of the present invention interproximally.Unexpectedly, the property of releasing these compositions correlateswith the opening up and/or flattening of the treated floss strandsduring flossing. This tendency of the loaded floss of the presentinvention to open up and flatten out during flossing allows the flossfibers:

a. to pass easily between teeth which are so closely spaced as to makeinsertion of typical floss difficult and painful,

b. to conform to the surface of the teeth,

c. to fit under the gum line at the gingival margin, and

d. to slip into subgingival areas in order to dislodge plaque bacteria,microflora etc. Historically, plaque, bacteria, pathogenic bacterialplaque etc., collect around the gum line and in various shallow pocketsthat form in this area. The subgingival plaque, bacteria, microfloraetc., requires regular disruption to control periodontal diseases.

As discussed above, floss has generally been waxed or bonded to reduceshredding. Such treatment results in the floss tending to hold its shapeduring flossing which results in the floss generally not flattening out,with less than optimum conformation to teeth surfaces and interproximalsurfaces. Thus, it is difficult to reach those remote interproximalareas without risk of pain and/or damaging delicate gum tissue. Incontrast, the loaded floss of the present invention, opens up tends toconform to surfaces and releases the loaded substances interproximallyduring flossing. This release mechanism results in:

1. the floss strands which are lubricated flattening to reduce shreddingand minimize stripping of the load prior to reaching the interproximalsites;

2. the floss stands flattening and conforming to the surfaces over whichthey are worked and reaching most remote interproximal surfaces;

3. the floss strands continuing to release the loaded substances duringflossing as the floss is moved over teeth, under the gum line and overthe interproximal surfaces; and

4. the floss being easier to manipulate over the interproximal sites andnear the gingival margin of the teeth where meticulous oral hygiene hasbeen impaired heretofore. These are historically the most bleeding proneareas of the mouth because heretofore they have been the most difficultto keep plaque free.

5. Finally, the flattening, conforming and lubricating properties of thefloss of this invention makes it much more pleasant to use, replacingthe frequently experienced pain and bleeding attendant with use ofordinary floss with a hedonically positive experience.

Thus, the release mechanism of the floss of the present invention allowsthe floss to reach the interproximal sites and physically remove plaque,while at the same time releasing the compositions of the presentinvention interproximally to assist in cleaning and/or treating theseinterproximal sites. This releasing of the compositions was quantifiedas follows:

Floss described in Example 39 of Table IV containing 40 mg of load/ydwas cut into 10, one yard lengths. The floss sections were dried at 104°F. for two hours and weighed. Unloaded floss was similarly heated andweighed. Two individuals flossed with five pieces each of the treatedfloss and with the unloaded floss. Both types of floss were again driedat 104° F. for two hours and reweighed. The average quantity of loadedactive ingredients released was established at 26 mg/yd with nosignificant variation between individuals or between pieces of floss.

The "load" of the compositions of the present invention into theinterstitial spaces between floss fibers also provides a suitablevehicle for effectively delivering other therapeutic substances to theinterproximal sites. The load can include very small quantities (say 100units per yard in the case of very active antibiotics) to large amounts(up to 60% by weight of anti-tartar or other chemicals requiring massaction) across a wide variety of therapeutic substances. Thus,chemotherapeutic treatment of interproximal sites can also be achieved.

For example, specific bacterial diseases in the oral cavity can be moreeffectively treated if various antibiotics can be introduced topicallyto specific interproximal sites. These include: penicillin, polymyxin B,vancomycin, kanamycin, erythromycin, niddamycin, metronidazole, andspiramycin which can be included in the compositions of the presentinvention and loaded into a chemotherapeutic floss of the presentinvention. Tetracycline is one preferred antibiotic agent in the flossof the present invention.

The topical application of various antibiotics to interproximal sites aswell as subgingivally is preferred over "systemic" treatments with thesesubstances. That is, the risk of adverse side reactions to the patientwhich accompanies most ingested systemic antimicrobials is reducedsubstantially. In addition, application of the antimicrobial to specificinfected areas can be achieved with a higher frequency, topically thansystemically. This assures higher antibiotic concentrations at thesite(s) of infection and a higher incidence of effectiveness in ashorter period of time. See Goodson Implant references 1979 to 1988.

Additionally, various chemical agents can be added to the floss asanti-plaque/anti-gingivitis agents including:

a. anti-plaque and anti-tartar substances such as the tetrasodium ortetrapotassium pyrophosphates and zinc chloride,

b. first generation agents which are antibacterial agents with limitedsubstantivity such as oxygenating compounds, quaternary ammoniumcompound, phenolic compounds and plant alkaloids such as sanguinarine,and

c. second generation agents which are antibacterial agents withsubstantivity such as chlorhexidine, either free base or as thegluconate or other suitable salt, alexidine, octenidine and stannousfluoride. Stannous fluoride and chlorhexidine antimicrobials in thevarious flosses the present invention are preferred embodiments of thepresent invention.

The loaded floss of the present invention containing variousantimicrobial substances offers the opportunity to disrupt subgingivalmicroflora and limit regrowth while also controlling supragingivalplaque. The release interproximally and subgingivally of substantivechemotherapeutic antimicrobials and the plaque disrupting compositionsof the present invention from the floss of the present invention tendsto:

a. disrupt or eliminate supragingival plaque, and pathogenic subgingivalflora, and

b. alter the environment interproximally and subgingivally sufficientlyto prevent regrowth of disease associated microorganisms. The resultingcontrol of plaque quantity and the periodontopathic microorganisms inplaque should help control gingivitis.

The first generation agents suitable for use in the floss of the presentinvention include:

quaternary ammonium compounds such as benzethonium chloride,cetylpyridinium chloride,

2. phenolic compounds such as thymol and eucalyptol in a mixture ofmethyl salicylate, benzoic acid and boric acid and phenol,

3. natural extracts (flavor oils) known to possess antimicrobialproperties, and

4. sanguinarine extract, alone or in combination with zinc chloride, orzinc chloride along.

It is suggested that the floss of the present invention containing theseanti-plaque and anti-gingivitis agents provides an important adjunct tothe prevention and control of gingivitis when used with regular personaloral hygiene procedures and professional care.

Surprisingly, the cleaning/coating compositions released from the flossof the present invention retain good surface active properties and areable to clear the interproximal areas of some cell debris, food debris,material alba, sugars, starches and other precursors to plaque. Thiscleaning is obtained with minimal foaming while simultaneously coatingthe interproximal surfaces with a thin neutral film containing theflavorants of the compositions. This neutral film is not metabolizableby resident oral cavity microorganisms.

By contrast, natural film formers such as lecithin-containing substancesand fats are known to form anti-attachment films on mouth surfaces butthese films are not suitable for the purposes of the present inventionsince they are metabolizable and are not neutral. Most of thesenaturally occurring coating substances support biological activityrather than form non-supportive inert films and as such, work oppositeof the suitable film formers of the present invention. See for example:Menaker, "The Biologic Basis of Dental Caries", Chapter 16: Gibbons andHoote, Ann. Rev. of Microbiol., 29, pp. 19-44; and Hayes, J. Dent. Res.,632, pp. 2-5 (1984).

As long as this transient inert coating of the present inventionremains, it:

1. restricts the subsequent adherence of plaque forming materials to theteeth, thus continuing the disruption of plaque formation:

2. continues to impart a "smooth" feeling to the mouth, and

3. prolongs the flavor perception after flossing.

These features are described in various Examples below. The prolongedflavor perception, described as a "clean, brushed feeling" between theteeth, is particularly novel and unexpected and makes flossing a morepleasant experience.

Most users of the floss of the present invention perceive a quitedifferent feeling in the mouth than is perceived with typical flosses.For example,

1. The treated floss slides comfortably between teeth producing lesspain, especially between "tight" teeth, and desensitizing agents reducediscomfort normally encountered with sensitive or bleeding gums.

2. The treated floss releases the compositions of the present inventiononto surfaces of teeth and gums more effectively cleaning theinterproximal sites.

3. The released compositions condition teeth and gums and leave themouth feeling exceptionally clean and smooth. The surfaces of the teethare smoother and shiny. The prolonged flavor perception is generallydescribed as "freshness" and is stronger, more natural tasting andpersists much longer with the released compositions of the presentinvention than when state-of-the-art, encapsulated "flavored" flossesare used under comparable conditions.

Frequency of cleansing is encouraged by the unique characteristics ofthe present invention. These cause the user to return to the presentinvention regularly, stimulated as much by the pleasant experiences asby conscious recall of "my mouth needs flossing". These characteristicsare: the product is exceptionally pleasant to use.

The various flavors and conditioners in the composition of the presentinvention are formulated to be as pleasant as a good quality candy mintand to contribute this pleasant taste over a longer-than-expected timeperiod thus enhancing the "it's working" perception without negative"dirty mouth" connotations due to the bad taste of released plaque anddebris. The latter is found to reduce frequency of use and undermine theregular cleansing advantage.

The feeling in the mouth is equally pleasant. A smooth, tingly"something's happening" feeling is perceived immediately upon flossing,followed by a clean, fresh, well lubricated mouth and teeth surfaceswhich unexpectedly persist much longer than mints, gums, breathfresheners and even mouth washes and toothpastes. Surprisingly, theinner teeth surfaces adjacent to gum tissue also feel clean and fresh--aphenomena perceived by most consumers only after gently prophylaxis by adentist.

Research shows that it is not unreasonable for a typical user of theinstant floss to use about 18 inches/use and to carry the dispenser inpocket or purse for use after snacks or meals.

The higher flavor levels which can be pleasantly incorporated into thefloss of the present invention, contribute to the plaque controllingproperties of this invention. For example, natural and synthetic flavorand sweetener agents as diverse as menthol, xylitol and glycyrrhizin areknown to be beneficial towards plaque control and are included in thecompositions of this invention. See, for example, Segal, J. Pharm. Sci.,74: 79-81 (1985) and Makkinen, J. Am. Dent. Assoc., 111: 740-741 (1985).

In addition to the cleaning and/or coating composition described above,preferred embodiments of the present invention use various viscositycontrol agents to impart certain viscosity characteristics to theproducts of the present invention. It is believed that in thesepreferred embodiments of the present invention, viscosity plays a rolein achieving optimum mouth feel and flavor retention characteristics ofthe present invention.

Viscosity control agents which are known in the food and consumerproducts, and not commonly used in floss, can be selected from naturaland synthetic gums such as: carragenan, gum tragacanth, methyl celluloseand derivatives there of such as hydroxyethyl methyl cellulose,polyvinyl pyrrolidone, and hydrophilic carboxyvinyl polymers such asthose sold under the trademark Carbopol 934.

Generally, about 0.01 percent to about 10 percent of one or moreviscosity control agents is used, see Table I. Often these substancesare used as dry powders directly incorporated as a third phase into themelt-emulsion mixture. With appropriate control of the active watercontent, some or all of these dry viscosity agents could be substitutedwith pre-gelled viscosofiers containing no free water.

In addition to the cleaning and coating compositions described above, apreferred embodiment of the present invention includes various solid,insoluble, particulates to:

1. further control viscosity of the melt-emulsion during manufacturing,

2. modify the solid texture of the completed product,

3. impart beneficial and pleasant mouth feel properties to the productwhich are perceived during use, and

4. optimize cleaning.

These particulates include approximately sized calcium carbonate, talc,silica and dicalcium phosphate. These are described in Table IV below.Most of these are used as dental abrasives. In addition to theseabrasives other particulates imparting beneficial properties includesalts which are generally insoluble in the compositions of the presentinvention such as tetra sodium pyrophosphate, tetra potassiumpyrophosphate and sodium bicarbonate.

In addition to the stabilizers, viscosity particulates, flavoring and pHbuffering ingredients; the compositions of the present invention canoptionally contain at least one humectant selected from the groupconsisting of glycerine, xylitol, sorbitol, hydrogenated glucose syrupand propylene glycol. Generally, such humectants are utilized in theproportion of about 0.1 percent to about 25 percent by weight based uponthe total weight of the composition. Preferably, the humectant isutilized in an amount of about 3 to 15 percent by weight, see Examplebelow.

Flavors, colorants, sweeteners, non-carcinogenic sugars and humectantsare also used to impart optimum cosmetic characteristics to thecompositions of the present invention.

Generally, the flavoring component is present as an oil, emulsified intothe composition by the surfactant component.

The conventional flavoring components are exemplified by the followingmaterials, menthol, anise oil, benzaldehyde, bitter almond oil, camphor,cedar leaf oil, cinnamic aldehyde, cinnamon oil, citronella oil, cloveoil, eucalyptol, heliotropine, lavender oil, mustard oil, peppermintoil, phenyl salicylate, pine oil, pine needle oil, rosemary oil,sassafras oil, spearmint oil, thyme oil, thymol, wintergreen oil, lemonand orange oils, vanillin, spice extracts and other flavoring oilsgenerally regarded as safe (GRAS) by health authorities.

Additional adjuvants can be added to provide color, flavor, orsweetening effects, as desired. Examples of suitable sweetening agentsinclude sorbitol, sodium cyclamate, saccharine, commercial materials,such as Nutrasweet brand of aspartame and xylitol. Citric acid or aceticacid is often utilized as a flavor additive. All types of flavoringmaterials are generally used in amounts of about 1.0 to about 20 percentby weight, preferably about 2.0 percent to about 15 percent by weight.

A buffering ingredient may also be added to the compositions of thepresent invention in order to prevent natural degradation of theflavoring components or therapeutically active ingredients. Generally,the pH of these compositions is adjusted from about 3.5 to about 8,depending on the chemistry of the active ingredient most requiringprotection. The buffering ingredients such an alkali metal salt of aweak organic acid, for instance, sodium benzoate, sodium citrate, sodiumphosphate, sodium bicarbonate or potassium tartrate is generally addedin an amount of about 0.1 to about 1.0 percent by weight. Otherbuffering agents such as weak organic acids or salts of weak bass andstrong acids such as boric acid, citric acid, ammonium chloride, etc.,can also be used in similar concentrations.

Stabilizers are often added to the compositions for additional control,such as:

a. sodium benzoate, sodium or potassium sorbate, methyl paraben,propylparaben and others approved for ingestion.

b. chemical oxidative control substances, such as ethylenediaminetetraacetic acid, BHA, BHT, propyl gallate and similar substancesapproved for ingestion. Concentration levels of these stabilizers complywith industry and regulatory standards.

Successful loading of the composition of the present invention into themulti-strand dental floss requires unique manufacturing processes otherthan those presently used to "wax" or "flavor" commercial flosses. Forexample, processes used for the addition of microencapsulated flavorsubstances, "flavor oils" or wax to floss do not provide for thequantity of load required for the present invention nor the "controlledrelease" of this loaded material interproximally during flossing. Thoseprocesses used for waxing, for example, primarily coat the outersurfaces of the bundle of floss strands.

In contrast, the compositions of the present invention are loaded insidethe floss in concentrations ranging from about 10% to about 100% byweight of the floss. This translates to from between about 10 mg andabout 100 mg per yard of floss. These loaded substances are thencontrollably released into the oral cavity during flossing at frombetween about 10 and about 80% of the load. For example, a flosscontaining 40 mg/yd of load will release between about 20 and about 32mg of load during flossing. Note, the rate of release of these loadedactive ingredients is easily controlled by varying the flossconstruction, the process of loading, and the composition of the loadedmaterial, providing additional novelty and utility to the presentinvention.

It is critical for the purpose of the present invention that much ofthis "loading" be accomplished in the interstitial spaces of the flossas distinguished from simply "coating" the outer surfaces of the bundleof floss strands. Much of what is called "Impregnation": in prior flossart is, upon careful examination, primarily "coating". Thus, thepressures and forces encountered during flossing allow for the loadedmaterial to be progressively released interproximally between the teethand under the gum line. This "interstitial loading" is particularlycritical in order to avoid "stripping" the floss of active ingredientswhile the floss is being inserted between the teeth and to avoidtransferring major quantities of loaded materials to the fingers duringflossing.

As the floss is worked through the contact point and moved gently underthe gumline the loaded substances of the present invention arecontinually released into those areas where plaque and debris aredifficult to clean and where irritation bleeding and bacterial infectiontend to occur.

In addition to interstitial loading a "secondary dusting" of the surfaceof the treated floss may be desired. This post addition of dry powdereffects the "hand" of the loaded floss and makes some floss easier tohold onto during flossing. The post added compositions include abrasivesetc., which can contribute to the efficacy of the floss. Thesesubstances are generally added at the rate of between about 0.08 mg andabout 9.0 mg per yard of floss and preferably between about 1.0 mg andabout 2.0 mg per 1 yard of floss.

Unexpectedly, the construction of dental floss, that is the method usedto twist the fibers into the finished floss, has been observed toinfluence the amount of the compositions of the present invention thatcan be loaded into the interstitial spaces around the fibers. Forexample in Table I, different floss constructions are described whichshow variations in load of up to about 400%. In Examples A-E thecomposition and the method of loading were held constant while the flossconstruction was varied. Specifically the composition described asExample 39 in Table IV was loaded into the various flosses by the methoddescribed in copending application Ser. No. 07/270,562 filed Nov. 14,1988, now U.S. Pat. No. 4,911,927.

                                      TABLE I                                     __________________________________________________________________________           FLOSS CONSTRUCTION       LOAD IN MG/                                   EXAMPLE                                                                              (all ends 140/68)                                                                              TWIST/INCH                                                                            25 yds OF F                                   __________________________________________________________________________    A      One blue and twisted around                                                                    2       250                                                  prepared by simultaneously                                                    twisting two pairs of two                                                     white ends previously twisted                                                 with one white single end.                                             B      Three white ends previously                                                                    2       500                                                  twisted at 1 twist/inch                                                       combined with two white and                                                   one blue end previously                                                       twisted at one twist/inc.                                              C      One blue end around a core of                                                                  2       1750                                                 two white ends twisted with                                                   blue end under lower tension.                                                 this in turn twisted around                                                   a core of three white                                                         previously twisted a core of                                                  three white previously twisted.                                               The wrap around (blue containing)                                             twist again under lower tension.                                       D      Three ends twisted                                                                              11/2   1000                                                 simultaneously. Each end                                                      comprised of two green ends                                                   previously twisted. Post                                                      drying left thread "fluffy"                                                   with many broken filaments.                                            E      Two ends twisted; each                                                                          11/2   600                                                  comprised of three white                                                      ends previously twisted at                                                    11/2  twist per inch.                                                  __________________________________________________________________________

The present invention will be further illustrated with reference to thefollowing examples which aid in the understanding of the presentinvention, but which are not to be construed as limitations thereof. Allpercentages reported herein, unless otherwise specified, are percent byweight. All temperatures are expressed in degrees Celsius.

In Examples 1 thru 4 various compositions of the present invention wereloaded into flosses of various construction and chemical makeup. Theloading was done by dipping the floss into an agitated bath containingthese compositions. The loaded floss was then hung in the air until cooland tested. The results are discussed in Table II below. Note, in all ofthese examples the surfactant used was PLURONIC F127, the coatingcomposition, Dow Corning Silicone 1500, the flavor IFF 101. There was nosubsequent powder treatment of the floss in these examples.

                                      TABLE II                                    __________________________________________________________________________           LOADING COMPOSITION                                                           SURFACTANT/                                                                            GLYCERINE/                                                                            FLAVOR (ml)/                                                 SILICONE SACCHARIN                                                                             SORBITOL OTHER ADDITIVES                              EXAMPLE                                                                              in g.    in g.   in g.    in g         FLOSS TYPE                                                                            RESULTS                 __________________________________________________________________________    1       2.5/5.5 0/.2      2/0      --         Bonded nylon                                                                          Useable, slightly                                                             oily feel               2      25.2/10.6                                                                              0/1.8     5/1    0.3 methocel K4M                                                                           Bonded nylon                                                                          Useable, some                                                                 separation on                                                                 standing                3       7.2/11.5                                                                              0/1.    3.5/14   0.1 methocel K4M                                                                           Bonded nylon                                                                          Useable, too                                                                  much silicone for                                                             optimal cleaning        4      10.8/7.2 0/1.    3.5/2    0.1 methocel K4M powder                                                                    Bonded nylon                                                                          Useable, better                                                               than                    __________________________________________________________________________                                                          (3)                 

In Examples 5 thru 8 various compositions of the present invention wereloaded into flosses of various constructions and chemical makeup. Theloading was done by passing the floss under tension and across fiberspreading devices, in an agitated bath containing these compositions.The loaded floss was then passed through a chamber charged withcarrageenan, wherein the chamber was fitted with rubber plugs withcarrageenan, wherein the chamber was fitted with rubber plugs providedwith slits which serve to remove excess powder. The loaded floss withthe post added powder was then tested. Note in all these Examples thesurfactant used was Pluronic F 127, the coating composition Dow CorningSilicone 1500, the Flavor IFF 101. Carrageenan was included in theloading composition in all examples. The results are set out in TableIII below.

                                      TABLE III                                   __________________________________________________________________________           LOADING COMPOSITION                                                           SURFACTANT/                                                                            GLYCERINE/                                                                            FLAVOR (ml)                                                                            OTHER                                               SILICONE SACCHARIN                                                                             SORBITOL ADDITIVES                                    EXAMPLE                                                                              in g.    in g.   in g.    in g     FLOSS TYPE                                                                            RESULTS                     __________________________________________________________________________    5      10.8/7.2  0/1.    3.5/2   Carrageenan 0.5                                                                        Unwaxed nylon                                                                         Dusting dramatically                                         (pre-gelled)     improves mouth feel         6      15.8/7.2  0/1.     8/2    Carrageenan 5                                                                          Unwaxed nylon                                                                         Improves mouth feel                                          powder                                       7      39.7/16.8                                                                               0/2.66 19.6/4.7 Carrageenan 1.77                                                                       Unwaxed nylon                                                                         Note in loading there                                        pre gelled plus  was a single pass thru                                       powder to dry    the chamber. Load was                                                         250 mg/25 yd dry to                                                           touch.                      8      39.7/16.8                                                                              --/2.66 19.6/4.7 Carrageenan 1.77                                                                       Oriented poly-                                                                        Load was 2000 mg/25 yd                                       pre gelled plus                                                                        ester 150/68/4                                                                        Dry to touch.                                                powder to dry                                __________________________________________________________________________

In Examples 9 thru 39 various compositions of the present invention wereloaded into a white nylon unbonded floss constructed from 6 strands of140 denier ×64 filaments. The loading was done by passing the floss thrua bath of the compositions of the present invention maintained at about210° F. The bath is provided with floss fiber spreading means and thefloss is passed through the bath at speeds ranging from between about 1and about 20 ft/sec. Excess composition is removed using dies andsqueegee arrangements. The loaded floss was then passed through achamber charged with various powder substances which are maintained in afluid state by a circulating charge of air passed through the chamber.Note, in all these Examples the surfactant used was Pluronic F 127; thecoating composition, Dow Corning Silicone 1500, the flavor IFF 101. Inthese Examples there was no glycerin added. The results are described inTable IV below.

Note: these post added powders can include: dicalcium phosphate,carrageenan, Methocel K4M, silica, sodium pyrophosphate, potassiumpyrophosphate and similar powdered substances which can improve the handand/or feel of the treated floss.

    TABLE IV      LOADING COMPOSITION  SURFACTANT/ FLAVOR (ml) DICALCIUM POWDER TREATMENT       SILICONE SACCHA- SORBITOL METHOCEL CARRAGEE- PHOSPHATE DICALCIUM     CARRA- METHOCEL   EXAMPLE in g. RIN in g. in g. K4M in g. NAN in g. in     g. PHOSPHATE GEENAN K4M  RESULTS       9 40/15 2.5 19.5/5 -- 18   --   +   10 50/15 2. 10/5 -- 18   --   + 11     50/15 2. 10/5 -- 18   --  + 12 50/15 2. 10/5 -- 18   -- + 13 50/15 2.     10/5 -- 18   -- + + 14 60/10 2.5 15/10 --  2.5 --   + 15 60/10 2.5 15/10     --  2.5 --   +  Each version of this series 16 60/10 2.5 15/10 --  2.5     -- +    had useful but different 17 40/15 2.0 15/15 13   -- --   +     properties. Loads ranged 18 50/15 2.5 10/7.5 -- -- 15 +    from between     about 500 to 19 50/15 2.5 10/7.5 -- -- 15  +   700 mg/25 yd. 20 50/15     2.5 10/7.5 -- -- 15   + 21 50/15 2.5 10/7.5 -- -- 15 +  + 22 50/20 2.5     10/0 -- 17.5 -- 23 50/20 2.5 10/0 -- 17.5 --   + 24 50/20 2.5 10/0 --     17.5 -- + 25 50/20 2.5 10/0 -- 17.5 -- + + 26 50/15 2. 10/5 18   -- -- +     +   Load was 500 mg/25 yd 27 45/18.5 1.8 14/4.5 16.2 -- -- + +   Load     was 600 mg/25 yd            Good mouth feel 28 50/20 2.5 13.75/xylitol     30 -- -- -- + +   Crystals of xylitol formed in            finished     product, coliquid effect            in mouth. 29 50/15 2. 10/Lycasin --     8  --     Improved mouth feel    powder 10 30 50/15 2. 10/Lycasin -- 8     -- + +   Improved mouth feel    powder 10 31 45/17.5 2.25 12.5/7.5  6.5     --    8.75     Powder improves mouth feel. 32 45/17.5 2.25 12.5/7.5  6.5     --    8.75 + +      " 33 47.2/20 2. 10/3.75 12.5 --   4.5 +    Loaded     800 mg/25 yd dicalcium            phosphate improves cleaning 34 47.2/20     2. 10/3.75 12.5 --   4.5  +   perception, carrageenen improves      mouth feel. 35 50/20 2.5 20/0 -- 15   15 + +   Loaded 800 mg/25 yd           Best of this group 36 200/80 10 IFF 343 Acid -- -- --  + Silica     instead  Sorbitol makes product different    Grape 45/100      of     methocel  from #45 and very useful 37 160/70 10 IFF 343 Acid -- --     Silica 50  + Silica instead  pH controlled at 3.5 with citrate    Grape     45/100      of methocel  buffer) Addition of silica improves     cleaning perception. 38 50/20 2.5 10  15   15 + +   Propyl gallate     (0.05%) and BHA            (0.05%) added to stabilize. Flavor     improves but yellows on storage            at 104° F. 39 50/20     2.5 10  15    15 + +   Propyl gallate (0.1%) and EDTA            (0.2%)     added to stabilize Flavor            and color stable after 7 months            at 104°      F.

Various cleaning and coating compositions suitable for use in thevarious flosses of the present invention are described in illustrativeExamples 40 thru 48 in Table V below. All percentages listed are byweight.

                                      TABLE V                                     __________________________________________________________________________    EX-   CLEANER COATING    SORBITOL                                                                             CARRAGEENAN                                                                             DICALCIUM PHOSPHATE                 AMPLE (%)     COMPOSITION (%)                                                                          (%)    VISCOSIFIER (%)                                                                         DENTAL ABRASIVE                                                                              FLAVOR               __________________________________________________________________________    40    PEG Stearate/                                                                         Silicone glycol/20                                                                       10     10        15              5                         40                                                                      41    Sodium lauryl                                                                         Carbowax/10                                                                              20     20        20             10                         sulfate/20                                                              42    Tween-80/30                                                                           Dodecane/10                                                                              30     10        10             10                   43    PEG Stearate/                                                                         Carbowax/10                                                                              20     15        25             10                         20                                                                      44    Sodium lauryl                                                                         Dodecane/15                                                                              25     10        15             10                         sulfate/25                                                              45    Tween-80/40                                                                           Silicone glycol/10                                                                       15     15        13              7                   46    PEG Stearate/                                                                         Dodecane/5 30     20        10             10                         15                                                                      47    Sodium lauryl                                                                         Silicone glycol/15                                                                       30     15        15             10                         sulfate/15                                                              48    Tween-80/20                                                                           Carbowax/20                                                                              20     15        15             10                   __________________________________________________________________________

Various cleaning and coating compositions suitable for incorporation ofvarious biological active ingredients into the various flosses of thepresent invention are described in illustrative Examples 49 to 57 inTable VI. Unless otherwise indicated all units are in percent by weight.

                                      TABLE VI                                    __________________________________________________________________________    INCORPORATION OF VARIOUS BIOLOGICAL ACTIVES                                                                          EDTA/  POLYOL                          EX-  SURFACTANT                                                                             SILICONE                                                                             CARRA-      SACCHA-                                                                             PROPYL OR     BIOLOGICAL               AMPLE                                                                              F 127    1500   GEENAN                                                                              FLAVOR                                                                              RIN   GALLATE                                                                              ABRASIVE                                                                             ACTIVE                   __________________________________________________________________________    49   42.75    14.25  15    10.7  2     0.2/0.1                                                                              silica tetra sodium                                                           (10)   pyrophosphate (5)        50   45       15     15    5.0   3     0.2/0.1                                                                              dicalcium                                                                            menthol (0.1)                                                          phosphate                                                                            thymo (0.2)                                                            (15)   eucalyptol (0.2)                                                              boric acid 90.5)                                                              methyl salicyate                                                              (0.2)                    51   55.5     18.5   --    9.0   1     0.2/0.1                                                                              sorbitol                                                                             cetylpyrininium                                                        (15)   chloride (0.1)           52   42.75    14.25  15    10    2.4     0/0.1                                                                              silica zinc chloride                                                          (15)   (0.5)                    53   42.75    14.25  10    10    2.9     0/0.1                                                                              silica strontium chloride                                                     (10)   (desensitizer) (10)      54   42.75    14.25  15    10    2.5   --     dicalcium                                                                            metrinidizol                                                           phosphate                                                                            (0.5)                                                                  (15)                            55   42.75    14.25  15    10    2.8   --     sorbitol                                                                             sanguinarine                                                                  extract                                                                (15)   (0.2)                    56   42.75    14.25  16    9.6   2.4   --     sorbitol                                                                             polymyxin B sulfate                                                    (15)   (1000 units/gram)        57   39.5     13.0   15    10    2.2   0.2/0.1                                                                              silica potassium nitrate                                                      (15)   (desensitizer)           __________________________________________________________________________                                                         (5)                  

EXAMPLE 58

Newburn et al. reported the effect of flossing with iodine impregnatedfloss in reducing S. mutans at specific interproximal sites. Their flosswas unwaxed floss, impregnated with 0.2% iodine plus 2% potassium iodide(KI). The control was unwaxed dental floss.

Specifically, Newburn et al. report that, ". . . although flossing alonereduces proportions of S. mutans, only the combination of flossing andiodine is effective in achieving a significant reduction. Still, threeiodine treatments were not enough to eliminate S. mutans permanentlyfrom any site".

Gibbons et al. were able to show the long-term effect of iodine ataccessible surfaces, but in their study it had little effect on molarinterproximal surfaces. Gibbons et al. applied iodine with a syringe anddental floss for 2 min. vs. Newburn's 10 sec/site. Newburn concludedthat there is no difference in the effectiveness of iodine whether it itused dried on the floss or with floss dipped into the iodine solution.

In contrast, when the polyvinyl pyrollidone iodine complex is includedin the preparations loaded into the floss of the present invention, theeffect on S. mutans interproximally is most favorable.

The polyvinyl pyrollidone iodine complex is a stable, effectiveantimicrobial with minimal staining that is ideally suited for additionto the floss of the present invention.

The PVPI floss preparation of the present invention can be formulated inthe following manner:

1. The required amount of surfactant is melted in a hot water bathmaintained at the lowest temperature possible to produce a smooth melt.

2. The required amount of polyvinyl pyrrolidone-iodine complex is addedwith vigorous mixing to achieve full dispersion, then immediately.

3. The silicone is mixed in until a thick cream is formed.

4. Step (3) is repeated with molten sorbitol and saccharin.

5. The remaining various solid materials, are then added, reserving theflavor oil until last, to reduce volatilization of the oil.

Suitable iodine complex preparations of the present invention areillustrated in Table VII.

                                      TABLE VII                                   __________________________________________________________________________    Surfactant                                                                          Coating                                  Iodine,                        Pluronic                                                                            Substance        Flavor          Antioxicants                                                                          Iodine salt, or                F127  Silicone                                                                            Sorbitol                                                                           Saccharin                                                                           IFF 101                                                                            Carrageenan                                                                          Silica                                                                            Propyl Gallate                                                                        Iodine Complex                 in %  1500 in %                                                                           in % in %  in % in %   in %                                                                              in %    in %                           __________________________________________________________________________    48.4  24.3  10   1.0   10.0 --     6.0 0.3     1.0                            45.0  22.7  15   1.0   10.0 --     6.0 0.3     1.5                            41.8  20.9  20   1.0   10.0 --     6.0 0.3     2.0                            51.7  26.0   5   1.0   10.0 --     6.0 0.3     0.5                            39.8  19.9  30   --    10.0 --     --  0.3     3.0                            __________________________________________________________________________

It will be apparent to one skilled in the art that other forms of iodinecan be substituted for the PVPI complex with relative ease. For example,potassium iodine can be incorporated into the molten sorbitol or freeiodine can be easily dispersed in the molten surfactant at step (1).

EXAMPLE 59

Langner et al. reported in 1984 on the use of tetracycline in variousdrug delivery systems such as these developed by Goodson. Weeks in 1980,Ciancio in 1976 and Loesche in 1976 have reviewed the use oftetracycline for the treatment of periodontal diseases.

According to Goodson, bacteria have been found to attach to oral tissuewith a remarkable degree of specificity. This attachment appears to bethe first step in the colonization process. It is reported that lowlevels of tetracycline applied topically affects the adhesion ofsuspected periodontal pathogens.

In shallow periodontal pockets, i.e., those no greater than about 3 mmin depth, local periodontitis conditions of patients should improve withregular use of the tetracycline in the load of the floss of the presentinvention. One would expect such treatment to dramatically change theperiodontal microflora and to rapidly decrease clinical signs ofgingival inflammation. When tetracycline is added to the floss inconcentrations ranging from between about 60 μg/yd to about 10 mg/yd,the pathogenic microflora of infected sites can generally be controlled.Generally, the tetracycline released for each interproximal surfaceflossed is between about 1 mg and about 10 mg, with total release forall 60 surfaces requiring at least about 64 mg/yd.

See Table VIII below for the formulations suitable for the tetracyclinefloss of the present invention.

The tetracycline floss preparation of the present invention can beformulated in the following manner:

1. The required amount of surfactant is melted in a hot water bathmaintained at the lowest temperature possible to produce a smooth melt.

2. The required amount of tetracycline is added with vigorous mixing toachieve full dispersion, then immediately thereafter,

3. the silicone is mixed in until a thick cream is formed.

4. Step (3) is repeated with molten sorbitol and saccharin,

5. and then the remaining various solid materials are smoothlyincorporated reserving the flavor oils until last, to reducevolatilization of the oils.

    __________________________________________________________________________    Surfactant                                                                          Coating                                                                 Pluronic                                                                            Substance                                                                           Sorbitol                                                                            Acid  Flavor                                                F127  Silicone                                                                            Solution                                                                            Saccharin                                                                           IFF 101                                                                             Carrageenan                                     in %  1500 in %                                                                           in %  in %  in %  in %                                            __________________________________________________________________________    48.4  24.3  10    1.0   10.0  --                                              45.0  22.7  15    1.0   10.0  --                                              41.8  20.9  20    1.0   10.0  --                                              51.7  26.0   5    1.0   10.0  --                                              39.8  19.9  30    --    10.0  --                                              __________________________________________________________________________

EXAMPLE 60

When the floss described above is processed in a specific manner, itbecomes unexpectedly adaptable to the inclusion of historically unstablestannous fluoride.

In the 1950's, Muhler, Bibby, Jordan and others reported their work withstannous fluoride dentifrices for reducing caries in children. Thesedentifrices were most successful commercially and are credited with thedramatic reductions in caries in children between the '50's and thepresent.

Stannous fluoride was replaced by sodium fluoride in about 1980 by mostfluoride dentifrice manufacturers because of the stability problemsencountered with stannous fluoride dentifrices.

For example, an aqueous solution of SnF₂ becomes turbid on standing dueto hydrolysis to Sn(OH)₂ or oxidation to SnOF₂. Stratemann in 1974described SnF₂ instability in aqueous systems.

In addition to the anticaries properties reported for SnF₂, there hasbeen extensive research directed to the antimicrobial properties of thissubstance. Kornman in 1986, Tehranirad in 1980 and Tinanoff et al. from1979 to 1988, have frequently reported on the antiplaque and gingivitiscontrol properties of topically applied SnF₂.

Additionally, Svanberg in 1983, reported on dental floss dipped in aSnF₂ solution. Keene et al. in 1977 reported working with SnF₂,topically applied to teeth, interproximally with floss. All of theseresearchers reported interproximal antimicrobial effects using theircrude floss delivery systems.

The unexpected stability of stannous fluoride in the preparations of thepresent invention were established using the techniques described byCamosci and Tinanoff, J. Dent. Res., 63: 1121-1125 (1984). The stannousfluoride is solubilized in one or more polyols such as sorbitol andadded to the preparations of the present invention in the absence ofwater. Preferably, the mixing and heating of these SnF₂ meltpreparations are carried out in the absence of oxygen and in metalvessels (to avoid fluoride reactions with glass).

Suitable chemotherapeutic flosses containing SnF₂ prepared in thismanner are described in the Examples set forth in Table IX below.

                                      TABLE IX                                    __________________________________________________________________________                                            (percent by weight)                   Surfactant                                                                          Coating            Flavor                SnF.sub.2                      Pluronic                                                                            Substance                                                                           Polyol/SnF.sub.2                                                                     Acid  IFF                   Concentration                  F127  Silicone                                                                            Solution                                                                             Saccharin                                                                           101 Carrageenan                                                                          Silica                                                                            Antioxidants                                                                         in melt-emulsion               in %  1500 in %                                                                           in %   in %  in %                                                                              in %   in %                                                                              in %   in %                           __________________________________________________________________________    68    16.8  Glycerin 3.9                                                                         1.9   9.4 --     --  --     0.39                           55.8  20.6  Sorbitol 13.0                                                                        1.3   9.3 --     --  --     0.39                           55.8  16.8  Sorbitol 13.0                                                                        1.3   9.2 --     --  --     0.78                           65.6  24.4  Sorbitol 10                                                                          --    --  --     --  --     0.30                           55.3  20.6  Sorbitol 10                                                                          1.3   12.8                                                                              --     --  --     0.30                           46.6  17.4  Sorbitol 10                                                                          1.1   10.8                                                                              14.1   --  --     0.30                           51.6  19.2  Sorbitol 10                                                                          1.2   12.0                                                                              --     6.0 --     0.30                           57.25 19.0  Sorbitol 10                                                                          0.75  7.5 --     5.2 propyl 0.30                                                                   gallate-0.3                           56.8  18.95 Sorbitol 10                                                                          0.75  7.5 --     5.1 propyl 0.30                                                                   gallate-0.3                                                                   EDTA - 0.6                            __________________________________________________________________________

A healthy gingival architecture is characterized by a sulcus of 1 to 3mm in depth, as measured between the crown of the tooth and thesurrounding gingival tissue. Healthy gingiva appears pink, with a firm,stippled surface, and it does not bleed either by mild provocation orspontaneously, and is not painful. The gingival sulcus of a healthyperiodontum has low numbers of principally facultative ormicroaerophilic, gram-positive, non-motile organisms and low numbers ofneutrophils.

Periodontal disease is a term used to collectively designate severalspecific diseases of the gingiva (gingivitis) and of the tissuessupporting the teeth (periodontitis). Organisms which grow in themicroenvironment of the periodontal pocket are implied as the cause ofthese periodontal diseases. As the disease becomes established, majorchanges occur in this environment. It becomes more anaerobic, populatedby Gram-negative, often motile organisms and frequently, intermittentlyinfused with large numbers of neutrophils. The environment becomesperfused by an increasing flow of gingival crevice fluid (GCF), theprimary aqueous milieu of the periodontal microenvironment.

Alterations of the gingiva seen with gingivitis are principally thoseassociated with inflammation. Gingiva appear red, swollen and bleedeasily. This condition is often associated with large numbers ofspirochetes and renders the gum tissue painful to touch or probe, and isfrequently associated with halitosis. The most common form of gingivitisis due to accumulation of supragingival bacterial plaque and as such istreatable by the SnF₂ floss of the present invention.

Periodontitis is a destructive form of periodontal disease. Thiscondition results in the loss of bone and collagen support of affectedteeth. Periodontitis is the result of local infection by specificmicroorganisms or groups of microorganisms and as such should beamenable to antibacterial therapy such as treatment with the SnF₂ flossof the present invention.

It has been established that even though SnF₂ is effective in killingperiodontal microorganisms at concentrations commonly used in mouthrinse preparations; delivery as a mouth rinse is inadequate for thetreatment of periodontitis. The rinse does not reach the periodontalpocket nor the interproximal sites of infection.

The release of the SnF₂ preparations from the floss of the inventionsubgingivally and interproximally in combination with the uniquemechanical action of the floss of the invention offers a newchemo/mechanical therapy to aid in the treatment of less severe sites ofperiodontitis. In deep periodontal pockets, i.e., 5 to 10 mm deep, theSnF₂ floss of the present invention has lesser effects since infectionin pockets of this depth is inaccessible to flossing and serves as areservoir for reinfection. When surgery and other treatments are usedfor these conditions, the SnF₂ floss of the invention shows promise as amaintenance product.

In addition to the anticaries, gingivitis and periodontal treatmentsdiscussed above there are additional antimicrobial treatments forspecific conditions that lend themselves to the SnF₂ floss of thepresent invention. One application is the pretreatment of patients forwhom oral surgical procedures are planned. It has long been recognizedthat any form of dental therapy which creates a laceration of thegingiva produces transient bacteremia. Therefore it would seem thatreduction of intraoral organisms such as S. mutans with the SnF₂containing floss of the present invention prior to surgical procedureswould be helpful. It is noted that S. mutans are also associated withendocarditis.

A second situation in which reduction of bacterial numbers appears toprovide therapeutic benefit is the surgical post operative maintenancephase. During this period of wound healing, surgical results should beimproved by controlling plaque, S. mutans, etc. with the SnF₂ floss ofthe present invention.

The stabilized SnF₂ flosses of the present invention offer a newtreatment for plaque control and for gingivitis control. As noted abovethe alterations of the gingiva seen with gingivitis are principallythose associated with inflammation, by specific microorganisms or groupsof microorganisms. It has been established that this disease is amenableto antibacterial therapy. However, control of this disease is not somuch a problem of killing pathogens as it is of altering local microbialecology. This control of the microbial ecology is achieved by:

a. regular disruption of the subgingival microflora, and

b. disruption or preferably, removal of the supragingival plaque.

It has been observed that gingivitis is a localized condition that isresponsive to treatment with the stabilized SnF₂ floss of the presentinvention. The release of stabilized SnF₂ preparations into "localized"inflammations and gingival eruptions delivers higher concentrations ofSnF₂ antimicrobial interproximally than achievable with any other SnF₂products such as rinses, gels, dentifrices, etc. This localized deliveryof SnF₂ disrupts the local microbial ecology sufficiently to control theinfection. Once disrupted, reorganization of the complex gingivitisecosystem present at a colonization site requires time. It has beenfound that repeated disruptions via regular flossing prevents suchreorganization and is an effective means of controlling the localmicrobial ecology including S. mutans.

Colonization of tooth surfaces by S. mutans is not uniform throughoutthe mouth but instead is highly localized to specific tooth surfaces. Asa result, dental caries activity is not uniformly distributed but tendsto develop between the teeth, around the necks of teeth, and in fissureson the occlusal surfaces. Therefore, treatments localized to specifictooth surfaces with the SnF₂ floss of the present invention areproposed. The resultant efficient delivery of SnF₂ in the preparationreleased from the floss; coupled with the mechanical cleaning oflocalized tooth surfaces promises superior anticaries clinicaleffectiveness.

It seems likely that such localized approaches which could affectindividual lesions or individual tooth areas could have widespreadapplicability. For example:

a. The application of orthodontic appliances creates new areas fordental plaque accumulation and constitutes a serious home care problem.The regular use of SnF₂ floss as part of orthodontic appliance use couldreduce the latrogenic disease liability of these appliances;

b. Mechanically sound dental fillings are commonly replaced due todeterioration of their margins which allow bacterial access to toothstructure and recurrent decay. S. mutans colonization accelerates atinterproximal restorations according to Keene et al. (1983). Eachreplacement enlarges the cavity and thereby structurally weakens thetooth. The regular use of SnF₂ floss of the present invention couldextend the longevity of such fillings and maintain a substantiallycaries free condition, especially at interproximal restorations; and

c. Radiotherapy patients experience accelerated caries which should betreatable with more frequent flossing with the SnF₂ floss of the presentinvention.

In these instances it is convenient to carry the stannous fluoride intothe melt-emulsion as a solution in a polyol which:

a. is compatible with the melt emulsion,

b. retains and protects the microbiological active properties of thestannous fluoride,

c. presents the stannous fluoride to interproximal sites in a form thatis readily solubilized by the fluids present so that it is available forsubstantial binding to tooth and gum surfaces.

One preferred polyol for stannous fluoride, glycerine, is described inthe literature as a carrier for stannous fluoride for water dilutablestannous fluoride rinses, see Yanke et al. (1982). The use of theglycerine-stannous fluoride solution in the melt emulsion process of thepresent invention is novel. Sorbitol is the most preferred polyol.Surprisingly, sorbitol forms a third phase, solid, at room temperaturein the melt-emulsion while simultaneously improving the mouth-feel andvarious physical properties of the finished floss.

One skilled in the art, having been taught the polyol-stannous fluoridesolution technology combined with the melt-emulsion technology of thepresent invention can appreciate that various alternatives can besubstituted for sorbitol, provided such alternative(s) are insoluble inthe bulk of the melt-emulsion and capable of forming a third-phase insaid melt-emulsion.

The various stannous fluoride preparations of the invention described inTable X below were prepared as follows:

1. A 10% solution of SnF₂ in glycerine was prepared by heating 90 gramsanhydrous glycerine USP to about 100° C., then adding 10 g of finelypowdered stannous fluoride USP, manufactured by Ozark, Mahoney, Tulsa,OK; using vigorous non-vortex stirring. The temperature of the heatingbath was slowly raised until the solution clarified.

2. A 3% solution of stannous fluoride in sorbitol was prepared byheating 97 g of anhydrous sorbitol powder (Rochette) in an oil bathmaintained at 160°-170° C. When the melt is clear and free of airbubbles, 3.0 g SnF₂ was added with vigorous, non-vortex stirring untilthe solution clarified. Stannous fluoride is unstable at elevatedtemperature in the presence of air, so for optimum results this step istimed to be completed immediately prior to the mixing step describedbelow.

3. Requisite quantities of surfactant and coating substance are heatedtogether in an oil bath controlled at 100°-100° C. As the surfactantmelts, the mixture easily emulsifies into a uniform "cream" withmoderate stirring.

4. To the surfactant, coating composition melt-emulsion of Step (3)above, the required amount of hot stannous fluoride/polyol solution isadded [either one of the solutions of stannous fluoride and polyoldescribed in Steps 1 and 2 above] with moderate stirring at 100°-110° C.until all components blend into a uniform emulsion.

5. The remainder of the ingredients, including solids, are addedcarefully with adequate mixing to ensure that solid particles areoccluded by molten surfactant. Due to the volatility of the variousflavor oils that can be used, it may be desirable to cool the mixtureslightly while retaining fluidity before adding the flavor oils.Antioxidants are most conveniently dispersed in the flavor oil prior toaddition to the molten emulsion. If desired, a portion of theantioxidants can be included in the stannous fluoride/polyol solutionand incorporated in the melt-emulsion in this manner.

Suitable stannous fluoride formulations can be prepared over a broadrange of concentrations by increasing the concentration of stannousfluoride in molten sorbitol to 10%, and following the method describedin Step 2 above.

                                      TABLE X                                     __________________________________________________________________________                                            (percent by weight)                   Surfactant                                                                          Coating                                                                             Sorbitol     Flavor                 SnF.sub.2                     Pluronic                                                                            Substance                                                                           Polyol/SnF.sub.2                                                                     Acid  IFF            Antioxidants                                                                          Concentration                 F127  Silicone                                                                            Solution                                                                             Saccharin                                                                           101 Carrageenan                                                                          Silica                                                                            Propyl Gallate                                                                        in melt-emulsion              in %  1500 in %                                                                           in %   in %  in %                                                                              in %   in %                                                                              in %    in %                          __________________________________________________________________________    48.4  24.3  10     1.0   10.0                                                                              --     6.0 0.3     1.0                           45.0  22.7  15     1.0   10.0                                                                              --     6.0 0.3     1.5                           41.8  20.9  20     1.0   10.0                                                                              --     6.0 0.3     2.0                           51.7  26.0   5     1.0   10.0                                                                              --     6.0 0.3     0.5                           39.8  19.9  30     --    10.0                                                                              --     --  0.3     3.0                           __________________________________________________________________________

EXAMPLE 61

Chlorhexidine can be successfully incorporated into various preparationsof the present invention according to Examples set forth in Table XI. Itis preferred to carry the chlorhexidine into the melt-emulsion either asthe free base or as a salt in a solution or uniform dispersion in anon-ionic surfactant compatible with the preparation. Typically, aPolyoximer 407, such as Pluronic F-127 (BASF), is used. However, a broadrange of other surfactants previously mentioned for the purposes of thepresent invention are also suitable.

The various chlorhexidine preparations of the invention described inTable XI below, can be prepared in several ways, for example:

1. Chlorhexidine free base is prepared as follows: Ninety nine grams ofPluronic F-127 is melted in an oil bath maintained at 130°-150° C. Onegram chlorhexidine base is dispersed with gentle mixing into the meltand stirred until a faintly opalescent solution is obtained. If greateramounts of chlorhexidine are required in the final formulations, 3% isreadily added in the same manner. Up to about 10% is compatible usingthis procedure.

2. Chlorhexidine dilactate is prepared as follows: A more readilywater-soluble version of the active ingredient can be compounded bymelting 194.2 grams of Pluronic F-127 at 150° C. and dispersing 4.0 gchlorhexidine as in (1) above. A commercial version of ChlorhexidineLactic Acid (88%) (Chemical Dynamics Corp., South Plainfield, N.J.) isused to provide a slight excess over the two equivalent weightsrequired. Thus, 1.8 g of the specified lactic acid is dispersed into thePluronic-chlorhexidine solutions above. The resulting dilactate hasgreater solubility than the free base chlorhexidine described in 1 aboveand the opalescent character noted previously clears as the reactionproceeds.

3. Chlorhexidine di-laurate is prepared as follows: Note: the di-lauratesalt of chlorhexidine was observed not to be soluble in water whilebeing very soluble in ethanol. It is expected that the long dodecenechain could be expected to influence substantivity and retention in theoral cavity. Controlled release of the free base chlorhexidine isexpected which in turn is substantive to the teeth and gums (a primaryrequirement for the therapeutic effectiveness of the drug).

The di-laurate appears to be soluble in the melt-emulsion of the presentinvention and can be readily prepared in the following manner:

a. Pluronic F-127 (96 g) are melted at 150° C. and 4.0 g chlorhexidineare dissolved as in (1) above.

b. Pluronic F-127 (96.4 g) are melted at 150° C. and 3.6 g (a slightexcess over the two equivalents required) of Lauric Acid 95% (Chem.Dynamics Corp., South Plainfield, N.J.) is mixed until dissolved.

c. The prior mixtures (a) and (b) are mixed thoroughly while holding at150° C.

4. Chlorhexidine di-gluconate is prepared as follows: Note, this watersoluble di-gluconate salt of chlorhexidine is the form of choice for anumber of therapeutic antimicrobials, including Peridex (TM) (Procterand Gamble) regularly prescribed in a 0.12% concentration mouth rinsefor the treatment of gingivitis. Typically, these products start with awater solution of chlorhexidine di-gluconate (20%) (ICI). However, topreserve the substantially non-aqueous formulations of the presentinvention the following procedure is used:

D-glucono-d-lactone (997) (Chem. Dynamics Corp. S. Plainfield, N.J.) ismoistened with slightly more than one equivalent of water (3.6 g) andheated at 75° C. in a closed vessel for 15 minutes. The crystalline,cool tasting, slightly sweet lactone is converted to a very acidic,thick syrup of gluconic acid.

a. Pluronic F-127 (96 g) is melted at 150° C.; and mixed with 4 gchlorhexidine as in 3(a) above.

b. The gluconic acid syrup described above (3.49 g) is mixed with 96.4 gof the melted Pluronic F-127 at 150° C.; resulting in a moderatelyopalescent solution.

c. The mixtures (a) and (b) above are then mixed thoroughly togetherwhile maintaining the temperature at 150° C. The resulting reactionproduces a material much less soluble in the non-ionic surfactant thaneither of the two staring materials and with continued mixing a thickcolloidal emulsions forms, thoroughly dispersed throughout thesurfactant.

It will be apparent to one skilled in the art that by following theprinciples taught here, a wide variety of chlorhexidine compounds can beformed in a non-aqueous environment, suitable for incorporation into thepresent invention.

Examples of some of these are included in Table XI.

                                      TABLE XI                                    __________________________________________________________________________    Surfactant                                                                          Coating             Flavor                Chlorhexidine                 Pluronic                                                                            Substance           IFF                   Concentration                 F127  Silicone                                                                            Chlorhexidine                                                                         Saccharin                                                                           101 Carrageenan                                                                          Silica                                                                              Sorbitol                                                                           in melt-emulsion              in %  1500 in %                                                                           compound (1)                                                                          in %  in %                                                                              in %   in %  in % as free base in               __________________________________________________________________________                                                    %                             72.0  17.3  free base-20                                                                          0.7   10  --     --    --   0.2                           57.2  12.4  free base-20                                                                          0.4   10  --     --    20   0.2                           65.4  15.5  free base-19                                                                          0.7   9.4 4.4    4.6   --   0.19                          79.0  16.7  free base-20                                                                          0.7   2.6 5.0    5.0   --   0.2                           80.0  20.0  free base-20                                                                          --    --  --     --    --   0.2                           78.5  19.5  free base-20                                                                          2.0   --  --     --    --   0.2                           65.0  15.0  free base-20                                                                          2.0   --  18.0   --    --   0.2                           65.0  15.0  free base-20                                                                          2.0   --  10     8     --   0.2                           57.5  12.5  free base-20                                                                          2.0   --  14.0   dicalcium                                                                           --   0.2                                                                phosphate                                                                           14.0                               50.0  10.0  free base-20                                                                          2.0   10  14.0   dicalcium                                                                           --   0.2                                                                phosphate                                                                           14.0                               71.0  17    d.lactate-10                                                                          2.0   --  --     --    10   0.4                           70.0  19    d.lactate-20                                                                          1.0   5.0 --     5.0   --   0.2                           51.5  10.5  d.laurate-10                                                                          2.0   5.0 6.0    5.0   20   0.4                           54.0  18    d.laurate-20                                                                          --    --  8.0    --    20   0.2                           65.0  15    d.gluconate-10                                                                        2.0   5.0 7.0    6.0   --   0.4                           55.0  15    d.gluconate-20                                                                        1.0   7.0 --     7.0   15   0.2                           57.5  12.5  d.gluconate-20                                                                        2.0   10.0                                                                              2.0    5.0   11   0.4                           71.0  17    d.laurate-30                                                                          2.0   --  --     --    10   0.4                           78.0  16    d.lactate-20                                                                          1.0   --  5.0    --    --   0.3                           55.2  11.8  d.lactate-20                                                                          1.0   7.0 5.0    --    20   0.4                           __________________________________________________________________________     (1) In surfactant Pluronic F127 as per 1-4 above.                        

EXAMPLE 62

The various sodium fluoride preparations of the invention described inTable XII below may be prepared as follows:

1. A 3% solution of sodium fluoride in sorbitol is prepared by heating97 grams of anhydrous sorbitol powder (Rochette) in an oil bathmaintained at 160°-170° C. When the melt is clear and free of airbubbles, add 3.0 grams NaF₂ with vigorous, non-vortex stirring until thesolution is clear. For optimum results this step is timed to becompleted immediately prior to the mixing step described below.

2. Requisite quantities of surfactant and coating substance are heatedtogether in an oil bath controlled at 100°-110° C. As the surfactantmelts, the mixture easily emulsifies into a uniform "cream" withmoderate stirring.

3. To the surfactant, coating composition melt-emulsion of (3) above therequired amount of hot sodium fluoride/sorbitol solution is added (oneof the solutions of sodium fluoride and polyol described in 1 and 2above) with moderate stirring at 100°-110° C. until all components blendinto a uniform emulsion.

4. The remainder of the ingredients, including solids, are addedcarefully with adequate mixing to ensure that solid particles areoccluded by molten surfactant. Due to the volatility of the variousflavor oils that can be used, it may be desirable to cool the mixtureslightly while retaining fluidity before adding the flavor oils.Antioxidants are most conveniently dispersed in the flavor oil prior toaddition to the molten emulsion. If desired, a portion of theantioxidants can be included in the sodium fluoride, sorbitol solutionand incorporated in the melt-emulsion in this manner.

5. Upon cooling the melt-emulsion can be formed into various shapessuitable for use in the methods of loading dental floss above.

Suitable sodium fluoride formulations can be prepared over a broad rangeof concentrations by increasing the concentration of sodium fluoride inmolten sorbitol to 10% following the method described in Step 1 above.

One skilled in the art, having been taught the sorbitol-sodium fluoridesolution technology combined with the melt-emulsion technology of thepresent invention can appreciate that various polyols or otheralternatives can be substituted for sorbitol provided suchalternative(s) are insoluble in the bulk of the melt-emulsion andcapable of forming a third-phase in said melt-emulsion.

                                      TABLE XII                                   __________________________________________________________________________    Surfactant                                                                          Coating                                                                             Sorbitol     Flavor                 NaF.sub.2                     Pluronic                                                                            Substance                                                                           NaF.sub.2    IFF            Antioxidants                                                                          Concentration                 F127  Silicone                                                                            Solution                                                                             Saccharin                                                                           101 Carrageenan                                                                          Silica                                                                            Propyl Gallate                                                                        in melt-emulsion              in %  1500 in %                                                                           in %   in %  in %                                                                              in %   in %                                                                              in %    in %                          __________________________________________________________________________    48.4  24.3  10     1.0   10.0                                                                              --     6.0 0.3     1.0                           45.0  22.7  15     1.0   10.0                                                                              --     6.0 0.3     1.5                           41.8  20.9  20     1.0   10.0                                                                              --     6.0 0.3     2.0                           51.7  26.0   5     1.0   10.0                                                                              --     6.0 0.3     0.5                           39.8  19.9  30     --    10.0                                                                              --     --  0.3     3.0                           __________________________________________________________________________

The present invention has been described in detail, including thepreferred embodiments thereof. However, it will be appreciated thatthose skilled in the art, upon consideration of the present disclosure,may make modifications and/or improvements on this invention and stillbe within the scope and spirit of this invention as set forth in thefollowing claims.

What is claimed is:
 1. A interproximal delivery system comprising:a)dental floss having from between two and 12 strands, each strandcontaining between about 100 and about 800 filaments, said floss havinga denier between about 300 and about 1200, and b) a cleaning preparationcomprising a surfactant and a coating substance selected from the groupconsisting of silicones, polydimethyl siloxanes, C₁₀ -C₁₅ hydrocarbons,normal paraffins having a clain length of 16 to 72 carbon atoms,paraffins with several loci of branching and unsaturation and carbowaxesor mixtures thereof said coating substance insoluble in said surfactant,loaded on said floss by either absorption or adsorption at from betweenabout 5% and about 100% by weight of said filaments, wherein:i.substantially each of said filaments is separated from one another bythe presence therein or thereon of the cleaning preparation; ii. saidinterproximal delivery system splays upon being worked betweeninterproximal surfaces; iii. said interproximal delivery system releasesfrom between about 10 and about 80% by weight of said cleaningpreparation upon splaying; and iv. said cleaning preparation:a) isloaded into said interproximal delivery system as a substantiallyaqueous free, hot-melt emulsion, b) is contained throughout theinterproximal delivery system, primarily in the area substantiallysurrounding each of the filaments with less than about 5% by weight ofsaid cleaning preparation on the outermost surface of said deliverysystem, and c) optionally contains up to about 50% by weight of one ormore active chemotherapeutic agents selected from the group consistingof: antimicrobials, antibiotics, antioxidants, tooth or gumdesensitizers, and anti-tartar agents.
 2. The interproximal deliverysystem of claim 1, wherein:a) the surfactant in the cleaning preparationis selected from the group consisting of: sodium lauryl sulfate, sodiumlauroyl sarcosinate, polyethylene glycol stearate, polyethylene glycolmonostearate, coconut monoglyceride sulfonates, sodium alkyl sulfates,sodium alkyl sulfoacetates, block copolymers of polyoxyethylene andpolyoxybutylene, allylpolyglycol ether carboxylates, polyethylenederivatives of sorbitan esters, propoxylated cetyl alcohol, blockcopolymers comprising a cogeneric mixture of conjugated polyoxybutyleneand polyoxylethylene compounds having as a hydrophobe a polyoxybutylenepolymer of at least 1200 molecular weight, a powdered salt of a fattyacid and a metal and a soap powderor mixtures thereof.
 3. Theinterproximal delivery system of claim 1, wherein the activechemotherapeutic agents are loaded into the floss at a rate betweenabout 10 mg/yd and about 100 mg/yd.
 4. The interproximal delivery systemof claim 1, wherein the active chemotherapeutic agent is released duringflossing at a rate between about 10% and about 80% by weight of saidload.
 5. The interproximal delivery system of claim 1, wherein the flossfurther contains a splaying supportive abrasive selected from the groupconsisting of silica, calcium carbonate, talc and dicalcium phosphate ormixtures thereof.
 6. The interproximal delivery system of claim 1,wherein the floss is further loaded with a splaying supportive tooth orgum desensitizer.
 7. The interproximal delivery system of claim 1,wherein the floss further contains a splaying supportive anti-oxidant.8. The interproximal delivery system of claim 1, wherein the floss isfurther loaded with a splaying supportive powder substance separate anddistinct from any active chemotherapeutic agents therein or thereon,said additional splaying supportive substance being selected from thegroup consisting of abrasives, gums, viscosity control agents, tartarcontrol substance and polyols or mixtures thereof.
 9. The interproximaldelivery system of claim 8, wherein an active chemotherapeutic agent isloaded into the floss at a rate between about 20 and about 50 mg/yd andwherein said additional splaying supportive preparation releases at arate between about 30% and about 70% by weight of the load.